This invention relates to a power tool and, more particularly, to an electric power driven tool provided with a bit accommodation unit for accommodating a spare bit for performing a desired task.
In known electric power tools of a pistol type structure having a tool body, a chuck is mounted onto its forward front, and a bit as a rotary tool blade is mounted in the chuck, which is driven by an electric motor. The motor is driven by operating a trigger switch incorporated in the tool body to thereby rotate and drive the bit mounted in the chuck to perform a desired task. Some of these known electric power tools are equipped with bit accommodation units each for accommodating another bit to be exchanged with one mounted in onto the chuck.
One example of the prior art electric power tools of the structure described above is disclosed in Japanese Utility Model Laid open (KOKAI) Publication No. 50 83672, in which an inner space is defined in the tool body at a side portion thereof. The inner space has a cover opened or closed by handling a gripping portion additionally provided for the tool body. This space is utilized for accommodating a bit to be exchanged with one used, and the bit is taken out from the space through the front end portion of the gripping portion by opening the cover.
The prior art further provides a bit accommodation unit, such as disclosed in Japanese Utility Model Laid open (KOKAI) Publication No. 53 153584, in which a bit accommodation case is disposed on an upper portion of a main handle provided for a tool body and a case cover is provided on the upper portion of the tool body to be opened or closed. A bit to be exchanged is accommodated in this case and taken out by opening the cover.
The prior art further provides a bit accommodation unit, such as disclosed in Japanese Patent Laid open (KOKAI) Publication No. 56 56388, in which a bit accommodation recess is formed inside a grip portion of the tool body and a bit accommodation case is disposed detachably in the recess. The bit case is mounted in the recess or taken out therefrom with the bit being accommodated in the case.
However, in the first type structure of the prior art, since the gripping portion is additionally provided on the tool body, the bit cannot be accommodated in the tool body which is not provided with such an additional gripping portion. In the first and second type structures of the prior art, it is required to open the cover to transfer the bit in or out of the tool body and close the cover after the transfer, thus being inconvenient and making complicated the structure of the tool body. Furthermore, there is a fear of damaging or losing the cover during the life of the power tool. Also, if the cover is not completely closed, the bit may fall out.
Still furthermore, in the type of the third structure of the prior art, since the bit accommodation recess is formed in the gripping portion of the tool body, spaces for accommodating or incorporating other elements such as a motor switch are limited, thus being not practical. The transfer of the bit in or out of the bit accommodation unit would be troublesome.